The long-chain omega-3 fatty acids are essential nutrients found primarily in fish. Most Americans eat little fish and, therefore, may be at risk for health sequelae. Clinical trail evidence generally indicates beneficial effects of fish oil supplementation: a) on cardiovascular disease incidence in patients with heart disease and, b) in terms of symptom amelioration in psychiatric patient groups. However, the effects of supplementation in the general population are unknown. The applicant and his colleagues have recently received support to conduct a randomized and placebo-controlled clinical experiment in healthy, adult community volunteers to test the effects of fish oil supplementation on markers for cardiovascular disease risk, negative affect and impulsivity. New observational evidence now also links low dietary intake or tissue levels of omega-3 fatty acids to poor cognitive functioning or dementia. The objective of the proposed research is to examine in the context of the described study the putative cognitive effects of supplementation in healthy adults who habitually consume little or no fish. This new, secondary outcome would entail administration of a battery of neuropsychological tests assessing working and general memory, psychomotor speed, attention and executive function at baseline and after at the end of the treatment period. Any demonstrable improvements in cognitive performance with supplementation would indicate both that dietary deficiency negatively affects cognition and that such performance decrements are reversible in a practical manner through increased omega-3 fatty acid consumption. PUBLIC HEALTH RELEVANCE: The long-chain omega-3 fatty acids are essential nutrients that are highly concentrated in the brain yet Americans typically consume very little of these nutrients in their diets. Since some evidence links low intake with poor cognitive function, the planned research would test whether taking a supplement of omega-3 fatty acids improves mental speed, information processing, and memory.